Silver is a desirable metal for use in various industries such as electrolytic anodes in the electroplating industry. In use, electrolytic silver anodes are placed in a plating bath with an object to be plated by electrodeposition of the silver anode. Various problems associated with silver anodes have plagued the prior art. One particular problem is caused by the inherent chemical composition of silver which reacts readily with ambient oxygen to form oxides when exposed to a sufficient amount of heat. Thus, silver oxide will form in this manner in accordance with the following equation: Ag +0.sub.2 +heat.fwdarw.Ag.sub.2 0. Since silver anodes are manufactured from molten silver, the molten silver absorbs oxygen during the manufacturing process resulting in the inclusion of undesirable oxides. Silver anodes including such oxides result in sludge being deposited in the plating bath. It also renders the electroplating process inefficient as the silver anode will be prevented from readily dissolving. Thus, the electroplating process is hampered by silver anodes which include silver oxide, even in small levels.
Another problem which arises with silver anodes is caused by impurities in the anodes, such as iron and sulfur, and the existence of insoluble particulate silver. When silver anodes including such impurities and insoluble particles are used, the electroplating process is hampered by unacceptable particles being deposited on the plated object.
Known processes for manufacturing silver anodes result in uniform crystal formation and large flat grains. In use, these silver anodes do not dissolve uniformly during the electrodeposition process. Instead, these silver anodes will dissolve along their grain boundaries so that the silver will flake and accumulate at the bottom of the plating tank.
Prior art inventors have attempted to solve some of the foregoing problems. However, no known prior art method of manufacturing silver anodes discloses a suitable efficient solution for the foregoing problems. U.S. Pat. No. 2,802,782 to Bayes et al. discloses an electroplating apparatus and a silver anode for use therewith. The silver anode may be manufactured by an extrusion process. U.S. Pat. No. 3,331,709 to Hill et al. discloses a method of producing silver anodes by removing oxygen from the silver. The method disclosed in the Hill et al. patent is particularly tedious and inefficient as it requires the initial manufacture of a silver billet, and subsequently reheating the silver billet in an annealing furnace.
The present invention solves all of the aforementioned problems by providing an efficient method of manufacturing fully annealed silver anodes.